Multimode analytical instruments, also referred to as multimode readers, are apparatus that can perform multiple analytical assays in a single instrument. Standard multimode readers, used within the life science industry, can measure the most common types of assays (i.e., applications, such as fluorescence, luminescence, and absorbance) in a single instrument. The use of a single instrument to perform these assays is advantageous over using multiple dedicated instruments to perform the same measurements. This lies in the fact that a multimode reader can provide ease of use, a better price performance ratio, and require less bench top area than multiple instruments.
Generally, these instruments have built-in general purpose (i.e., white) light sources, such as halogen lamps and xenon flash lamps, and general purpose detectors such as photomultiplier tubes (PMTS) and silicon photodiodes. The instruments also typically include optical filters mounted into wheels or slides, and application specific beamsplitters installed into slides, or into revolver like mechanisms. Multimode readers may also combine filter-based and monochromator-based technology. While components are configured to perform a variety of types of assays, expanding the multimode reader to perform new assays and new applications was often difficult. From a hardware point of view, specific applications may involve accessing a multitude of driven stages for selecting the correct combination and adjustment of filters, beamsplitters, apertures, and light-guides, for example. In these devices, enabling new applications of a given technology required retrofitting specific optical filters and beamsplitters. Adding new applications often required substantial redesign.
The implementation of standardized application cartridges having a standard form and shape, and configured with components arranged for specific applications, or types of applications has improved the ability add applications. One example of a system that employs application cartridges is the Paradigm® system from Molecular Devices. Application cartridges substantially reduce the amount of redesign and retrofitting involved in adding applications to a system. However, with the exception of applications that employ absorbance-based measurements, the advantages have largely been realized for filter-based technologies. Applications that involve fluorescence-based and luminescence-based measurements and that also use monochromator-based technology have not been successfully implemented in standard cartridges. In general, the standard cartridges lack the size to accommodate such applications. It would be desirable for a multimode reader to be truly expandable so that applications can be added to the system without any significant redesign.
Detection systems that use multimode readers typically take measurements from samples in microplates. Cell imaging systems have recently included functions that incorporate components typically found in detection systems. For example, detectors may be incorporated for performing label-free detection to measure changes in refraction index of microplate bottoms after reagent addition. Detection systems incorporate illumination and injection functions that may be advantageously used by cell imaging systems. For example, the illumination components in detection systems such as photodiodes may be used in a cell imaging system to perform epifluorescent microscopy.
There is a need in the art for a detection system with multimode reader capabilities that would not require any redesign in incorporating new technologies and new applications, including those that involve monochromator-based technology in fluorescent and luminescent measurements. There is also a need in the art for a detection system that would permit an interface with a cell imaging system in order to enable the advantageous use of components in the detection system in the cell imaging system.